Magnetic apparatus.



K. L. CURTIS.

MAGNETIC APPARATUS.

APPLICATION FILED FEB. 12. 1915- o y F i aofi lliliifleses .Zivveniar UNITED STATES PATENT OFFICE.

KENNETH L. CURTIS, OF BOSTON, MASSACHUSETTS, ASSIGNOB TO ALBERT AND T. I. ANDERSON MANUFACTURING COMPANY, OI BOSTON, MASSACHUSETTS, A CORPORA- TION OF MAINE.

MAGNETIC APPARATUS.

Specification of Letters Patent.

Patented Nov. 2'7, 1917.

Application filed February 12, 1915. Serial No. 7,878.

To all whom it may concern:

Be it known that I, KENNETH L. CURTIS, a citizen of the United States, residin in Boston, in the county of Suffolk and tate of Massachusetts, have invented an Improvement in Magnetic Apparatus, of which the following descri tion, in connection with the accompanying rawings, is a specification, like characters on the drawings representing like parts.-

This inventionv relates to a magnetic apparatus especially adapted among other uses for safeguarding electric circuits.

To this end, the magnetic apparatus is provided with a permanent magnet member, and with a magnetizable member, which is constructed so as to avoid detrimental efiect upon the permanent magnet member of a reverse current of high value in the circuit su plying the magnetizing force.

he magnetic apparatus is especially protected, and in the present instance, attracts the permanent magnet member under normal conditions, and the magnetizable member is constructed so as to repel the permanent magnet member under a wide range of reverse current values or strengths, as will be described.

These and other features of this invention will be pointed out in the claims at the end of this specification. I

Figure 1 represents one form of circuit breaker whose mOVablG -Zmember is operatively connectedwitn a magnetic apparatus embodying this invention, the circuit breaker being inits closed position.

Fig. 2, a like view with the breaker in its open position and the magnetic apparatus in its operative position, and

Figs. 3 and 4, details of the magnetic apparatus shown in Fig. 1.

In the present instance I have illustrated my invention in connection with a known form of circuit controlling. device, com-, monly known as a circuit breaker, which is substantially the same as that shown and described in U. S. Patent No. 1,050,592 dated January 14, 1913.

The circuit breaker herein shown consists of a movable contact member or brush 10, which cooperates with fixed terminals or contact members 12, 13, secured to a panel or board 14 and provided with terminal studs or bars 15, 16. The movable contact member 10 is suitably secured to a movable sup ort shown as a lever 17 which is pivote at 18 to a supporting frame 19, and sald lever is moved into its 0 erative position by an electromagnet 20, w ose armature or core 21 is connected by a link 22 with an arm 23 on a segmental gear 24, mounted to turn on a pivot 25, and having its teeth 26 in mesh with a pinion 27 attached to a crank disk 28 on a shaft 29, and provided with a crank pin 30, which is connected by a link 31 to the carrier or lever 17 for the movable contact member 10. By energizing the solenoid or electromagnet 20, in a manner well understood, the contact member 10 is moved from its open position shown in Fig. 2 into its closed position shown in Fig. 1, and said contact member is locked in its closed position by a locking lever 35, whose upper end moves under a shoulder 36 on the segmental gear 24. The locking lever 35 is moved into its operative position by gravity acting on the armature 37 of a tripping magnet or coil 38, which has its core or rod 39 connected to the center pin 40 of toggle levers 41, 42. By energizing the tripping coil, the core 39 is attracted and the toggle levers 41,

42 are moved into the positlonshown in Fig. 2, which action withdraws the lockin lever 35 from under theshoulder 36, and permits the contact member 10 to be moved 1nto its open position, so as to open the circuit which includes the breaker and is represented by the terminal bars or rods 15, 16. A fuller explanation of the operation of the circuit breaker herein shown may be had by reference to the patent above referred to. In accordance with the present invention a magnetic device, as will be described, is provided for opening the breaker by a reverse current in the circuit. The magnetic device com rises a permanent magnet member which 1s operatively connected with the circuit breaker, and a magnetizable member which cooperates with one of the terminal a wide variation in the strength or value of the reverse current, without detrimentally affecting the amount of magnetism in the permanent magnet to such extent as would cause the latter to be retained in its attractive position and thereby become inoperative to open the breaker.

\ In the present instance I have shown one construction of magnetizable member preferred by me for accomplishing this result.

To this end, the magnetizable member is composed of two sections 50, 51 of magnetizable metal and of substantially the same area in cross section, and separated by magnetic gaps or spaces 52, which are bridged by connecting arms or strips 53 of magnetizable metal and which are materially thinner than the sections 50, 51.

The section 50 is preferably made sub stantially square in form, and as shown in Fig. 3, comprises substantially parallel side bars 90, 91, connected at their upper ends by a cross bar 92 and having extended from their lower ends toward each other arms 93, 94, which are separated at their ends to form an air gap 55, and the connecting strips 53 are attached to the arms 93, 94, and are extended from the opposite sides of the said gap substantially at right angles to said arms. The lower sections 51 may have se cured to them thin brass pieces 56, against which the ends of the permanent magnet 60 strike, when the latter is attracted by the sections 51.

The permanent magnet 60 is preferably made as a horse-shoe magnet and is attached at its center to an arm 61 on a sleeve 62, mounted on a pivot 63 carried by a bracket 64, secured to the board or panel 14. The sleeve 62 is provided with a projection or arm 66, which is designed to strike the end of a rod 67, mounted to slide in an opening through the panel or board 14: and having its opposite end adapted to strike against an arm 68 on the toggle lever 42. It will thus be seen, that when the permanent magnet 60 is repelled from the magnetizable member, it will drop into substantially the position shown in Fig. 2, and acting on the rod 67 will move the latter so as to break the toggles 41, 42 and move the locking lever 35 so as to release the movable contact member 10 and permit the latter to be moved into its open position by gravity or otherwise.

Provision is made for automatically restoring the permanent magnet into its normal or attracted position, and this may be effected as herein shown, for which purpose the segmental gear 24: is provided with an arm 70, to which is connected one end of a rod 71, extended through the board 14 and provided with a latch 73, which cotiperates with a bent arm 74 on the sleeve 62 and hooks over the said arm when the movable contact member 10 is in its open position shown in Fig. 2, so that when the said contact member 10 is moved into its closed position, the latch rod 71 pulls the permanent magnet up into its vertical position into the field of the magnetizable member. When the permanent magnet has been moved so that it comes within the influence of the magnetizable member, the latch 73 is' disengaged from the arm 74, by a cam or inclined piece 75 on the rod 71 riding over a stationary device or pin 76, which elevates the hooked end of the latch above the arm 74, and leaves it in position to drop down into engagement with said arm when the breaker is opened as above described.

By reference to Figs 3 and 4: it will be seen that the strips or parts 53 which lead from the upper section 50, form branches from the magnetic circuit through the upper section, and being materially reduced in cross section, are saturated with magnetism at the minimum desired value or strength of the reverse current, and when saturated, the magnetism repels the ermanent magnet and causes the breaker to be opened as above described. By reason of the fact that the permanent magnet is repelled when the strips 53 become saturated or approximately so, which takes place at the minimum desired value or strength of the reverse current, any material increase in the strength of the reverse current does not have a detrimental effect upon the strength of the permanent magnet so as to render the device inoperative, as would be the case if the strength of the permanent magnet was weakened or the polarity of the same reversed by the increased or higher value of the reverse current. The repulsion of the permanent magnet takes place when the strips approximate magnetic saturation, and any material increase in magnetism in the upper section 50 of larger cross section, due to the increase in the strength of the reverse current, does not have a detrimental effect upon the permanent magnet. In other words, the magnetism induced in the upper section 50 created by a reverse current of minimum strength is caused to flow to the strips 53 by the presence of the air gap 55 in the upper section 50, and when the magnetism is. increased in the upper section 50 by a stronger reverse current in the circuit, the increased magnetism is sufficiently strong to flow across the gap 55 and only a portion sufiicient to saturate the strips 53 will flow to latter, consequently the increase in magnetism in the magnetizable member does not have a detrimental effect on the permanent magnet. The weakening of the strength of the permanent magnet by the increased magnetism in the magnetizable member would be detrimental, because the repelling force would be weakened to such extent as not to be able to repel. the permanent magnet and the strips 53 practically constitute branches thereby open the breaker. The reversal of the polarity in the permanent magnet by the reverse current of high value would also be detrimental, because under such conditions, the permanent magnet would be attracted by the magnetizable member and would remain in its inoperative position.

" It will therefore be seen that with a magnetic apparatus which avoids the above mentioned detrimental effects upon the permanent ma et, all values of the reverse current in t e circuit, even such as are encountered in short circuits in railway practice, are taken care of and rendered harmless.

By reference to Fig. 3, it will be seen that which lead from a magnetizable circuit 1. The combination formed by the upper section 50, and in practice said branches may be made as separate strips secured to the upper section as herein section. I

I have herein shown the magnetic apparatus as employed for operating a circuit breaker, but it is not desired to limit the invention to this articular use, as it may be employed for ot er purposes. So also I have herein shown one construction of mag- 1181310 apparatus havmg the functions above describe but it is not desired to limit the invention to the herein shown.

Claimsparticular construction with an electric circuit provided with a circuit controlling device having a member capable of being I moved to open the said circuit, of mechanism for moving said movable member to close said circuit, a locking device for looking said member in its closed position, a magnetic apparatus having a magnetizable member under the influence of the current flowing through said circuit, and a permanent magnet member cooperating with said magnetizable member and pivoted to move toward and from the latter, a device cooperating with said permanent magnet member and with said locking device to unlock said manent m at mem thickness in fixed relation to each other, and

a permanent magnet member cooperating with the section of less thickness.

4:. In a magnetic apparatus of the characterdescribed, in combination, a magnetizable member having sections of substantially the same thickness spaced apart and metallically connected by a section of less thickness, and a permanent magnet member cooperating With said magnetizable member.

5. In a magneticapparatus ofthe character described, in combination, a magnetizable member comprising substantially parallel side bars, a cross bar connecting said side bars, arms rigidly attached to said side bars at their lower ends and extended toto leave an air gap, sections extended from ends cooperating with said sections.

6'. In a magnetic apparatus, in combina- 2 .tion, a permanent magnet member, and a' magnetizable member cooperating therewith j 'and'const'ructed so as to reduce to a substaml i said arms on opposite sides of said air gap, and a permanent magnet member having its.

tially constant value at a pole of said magnetizable member, the magnetizing effect, 96

which may flow through the circuit sup 1%- ing the magnetizing force "irrespective of t e values of the reverse currents or of the length of time the reverse currents may flow in said circuit.

In testimony whereof, I have signed my name to this specification in the presence of two subscribing witnemes. Y 

